Abstract
Objective: This study tried to evaluate whether a methacholine test may be influenced by the seasons. Methods: We considered 4826 consecutive subjects with normal spirometry (50.53% males; age: 35.1+-16.2; forced expiratory volume in one second: 99.5+-13.0%) who underwent a methacholine test for suspected asthma symptoms between 2000 and 2010. They were subdivided into four groups, like the seasons, according to the test dates. Results: A total of 1981 (41%) resulted normal (no PD 20 was obtained with 2400 μg of methacholine); the others showed a mean LogPD 20 of 2.52+-0.5 μg. The number of subjects with bronchial hyper-responsiveness (BHR) found in autumn (789, 62.3%) was higher than in summer (583, 56.7%; P=0.03). A higher number of females and overweight/obese subjects showed a BHR in autumn compared with the other seasons. The spring mean LogPD 20 value (2.48+-0.48 μg) was lower if compared with the one measured in summer (2.59+-0.49 μg; P=0.05). LogPD 20 value was lower in females and non-smokers in spring compared with summer (P<0.05). Overweight/obese non-smokers showed a lower LogPD 20 in spring and autumn compared with that in summer (P<0.05). Autumn was a risk factor (OR: 1.378; P=0.001) for BHR (using a PD 20 <2 400 μg as BHR limit), while spring (OR: 1.330; P=0.021) and autumn (OR: 1.331; P=0.020) were risk factors for a more severe BHR (using a PD 20 <400 μg as BHR limit). Conclusion: There was a higher probability of finding BHR in outpatients with suspected asthma in autumn and spring compared with summer. Spring is the season where BHR may be more severe. Females and overweight/obese subjects were those mainly involved in this seasonal variability of BHR.
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer